A child is born into the world, immediately they are hated and not cared for by near anybody they meet. They are labelled that of a freak for the things that they cannot control, and are nearly entirely shunned, those that care cannot do enough to help, possibly losing care themselves. When things go too far the child is broken, a shell of what they formerly were, cheerfulness and innocence, nothing for them anymore.
From this they learn something, nobody will care for them and emotions hold them back. They have something awaken within them, a darkness, a demon that changes them completely. They begin to care solely for themselves, live only for themselves. They begin to question their entire personality and life. They become darker, more vicious, less caring and compassionate. Slowly they become worse and worse as time passes, until they become completely encased in this evil possessing them.
When this occurs they are completely gone, only drastic measures can even hope to bring one back from this state. It takes extreme effort and time to even hope to have that happen, one completely seduced by the monster they have become has a harsh road back, it can take years of pain, memories, hardships and who knows what?
What reverses a being who's been afflicted with this? There are very powerful forces that can do just the trick, the energies known as compassion, care, kindness, friendship, all of these can be an asset to greatly change somebody back, but there is one above all. Love. It does not have to be romantic love, any love, friendship, family, romance, any kind of love whatsoever, as long as they know it exists and are surrounded by people that are like this with them, it can change their lives completely.
This can remove the demon afflicting them, they can finally understand everything they couldn't before, the loneliness afflicting them gone, their darkness being petered out and everything being clearer and brighter just from the sheer power of things such as love. Now, they can finally be complete and healed. That is the power the thing known as love can have.
"There's only one thing that can heal the heart... Only one... It's love."